May 15-20 Severe Threat

[jojo762]

12Z GFS is certainly impressive across C OK by 00z Thursday. Nicely backed surface winds, 30-40kt southerly LLJ, 50kt SWly flow at 500mb, and strong instability... the stronger upper level winds are lagging the stronger H5 winds a bit, but 50kts at 250mb is still okay. 

[Radtechwxman]

10 minutes ago, jojo762 said:

12Z GFS is certainly impressive across C OK by 00z Thursday. Nicely backed surface winds, 30-40kt southerly LLJ, 50kt SWly flow at 500mb, and strong instability... the stronger upper level winds are lagging the stronger H5 winds a bit, but 50kts at 250mb is still okay. 

Did you mean 0z Fri? 0z Thurs would imply Wed night

[jojo762]

6 minutes ago, StormChaser4Life said:

Did you mean 0z Fri? 0z Thurs would imply Wed night

You know I meant 7pm Thursday lol. 

[jojo762]

The 12Z CAMs are looking fairly juicy for Tuesday, especially across NW OK into SC/SW KS... Most of them show some convective clusters, with several discrete supercells mixed in across this area, especially the HRW-NMMB which shows numerous discrete supercells across the aforementioned area. Something to note is they are hinting at the possibility of fairly early CI, possibly by 17-19Z.

[CGChaser]

4 minutes ago, jojo762 said:

The 12Z CAMs are looking fairly juicy for Tuesday, especially across NW OK into SC/SW KS... Most of them show some convective clusters, with several discrete supercells mixed in across this area, especially the HRW-NMMB which shows numerous discrete supercells across the aforementioned area. Something to note is they are hinting at the possibility of fairly early CI, possibly by 17-19Z.

Similarly HRRRx has initiation ~20z but has essentially one cell through 00z. Admit, I was somewhat perplexed at reading SPC disco this morning regarding moisture issues.

[jojo762]

5 minutes ago, CGChaser said:

Similarly HRRRx has initiation ~20z but has essentially one cell through 00z. Admit, I was somewhat perplexed at reading SPC disco this morning regarding moisture issues.

I was as well, as all models are pretty on board regarding moisture being sufficient. Same forecaster has been issuing the outlooks for Tuesday for days now, will get a fresh opinion here pretty quick from a different forecaster with the 1730z D2.

[jojo762]

DAY 2 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
1226 PM CDT MON MAY 15 2017  
  
VALID 161200Z - 171200Z  
  
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM  
NORTH-CENTRAL KS AND ADJACENT FAR SOUTHERN NE SOUTHWARD THROUGH  
WESTERN OK AND THE EASTERN TX PANHANDLE INTO WESTERN NORTH TX...  
  
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE  
ENHANCED AREA FROM PORTIONS OF THE UPPER MISSISSIPPI VALLEY TO THE  
SOUTHERN GREAT PLAINS...  
  
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE  
SLIGHT RISK AREA FROM WESTERN PORTIONS OF THE UPPER PENINSULA OF  
MICHIGAN AND THE UPPER MISSISSIPPI VALLEY TO THE SOUTHERN GREAT  
PLAINS...  
   
..SUMMARY  
  
SEVERE THUNDERSTORMS WILL BE POSSIBLE FOR TUESDAY INTO TUESDAY NIGHT  
FROM PORTIONS OF THE SOUTHERN GREAT PLAINS TO THE UPPER MISSISSIPPI  
VALLEY REGION, WITH THE GREATEST SEVERE WEATHER RISK EXTENDING FROM  
NORTH-CENTRAL KANSAS AND ADJACENT FAR SOUTHERN NEBRASKA SOUTHWARD  
THROUGH WESTERN OKLAHOMA AND THE EASTERN TEXAS PANHANDLE INTO  
WESTERN NORTH TEXAS. LARGE HAIL AND DAMAGING WINDS WILL BE THE  
PRIMARY CONCERNS WITH THIS ACTIVITY. A FEW TORNADOES WILL ALSO BE  
POSSIBLE, ESPECIALLY FROM PARTS OF WESTERN OKLAHOMA AND THE EASTERN  
TEXAS PANHANDLE INTO CENTRAL KANSAS.  
   
..SYNOPSIS  
  
A MIDLEVEL CYCLONE AND ACCOMPANYING SHORTWAVE TROUGH IS FORECAST TO  
TRACK FROM PORTIONS OF THE SOUTHWEST STATES TO THE SOUTHERN AND  
CENTRAL GREAT PLAINS, EMBEDDED WITHIN A BROADER AREA OF CYCLONIC  
FLOW OVERLYING THE WESTERN STATES. PRESENT WATER VAPOR IMAGERY  
DEPICTS MULTIPLE MIDLEVEL SPEED MAXIMA AND OTHER PERTURBATIONS  
EMBEDDED WITHIN A LONG FETCH OF SOUTHWESTERLY FLOW AHEAD OF THE  
CYCLONE. AS THE CYCLONE AND PRECEDING SPEED MAXIMA APPROACH THE  
SOUTHERN AND CENTRAL PLAINS, THE DRYLINE OVER THE HIGH PLAINS WILL  
SHARPEN -- ESPECIALLY FROM WESTERN KS TO WEST TX. LEE TROUGHING  
COINCIDENT WITH THE DIURNALLY DEEPENING DRYLINE CIRCULATIONS WILL  
CONTINUE TO FOSTER POLEWARD TRANSPORT OF LOW-LEVEL MOISTURE FROM THE  
WESTERN GULF, EAST OF THE DRYLINE, NORTHWARD TO THE UPPER  
MISSISSIPPI VALLEY (SOUTHEAST OF A SLOW-MOVING BOUNDARY DRAPED  
ACROSS THE NORTH-CENTRAL STATES). GIVEN THE POSITION OF A STAGNANT  
SOUTHEAST STATES/NORTH GULF SURFACE RIDGE -- THAT WILL SLOWLY ABATE  
FROM THE WEST -- THE CORRIDOR OF STRONGEST MOISTURE RETURN WILL  
LIKELY BE CONFINED FROM SOUTH-CENTRAL TX THROUGH WESTERN OK AND  
VICINITY AND THEN NORTHEASTWARD THROUGH THE MIDDLE MISSOURI VALLEY  
AND INTO THE UPPER MISSISSIPPI VALLEY.  
   
..PORTIONS OF THE SOUTHERN AND CENTRAL GREAT PLAINS  
  
BY MID/LATE AFTERNOON, DIURNAL HEATING OF THE WARM/MOIST SECTOR EAST  
OF THE DRYLINE (SURFACE DEWPOINTS GENERALLY IN THE MIDDLE 60S) WILL  
SUPPORT A CORRIDOR OF 2000-3500 J/KG OF MLCAPE, AIDED BY  
MOIST-LAYER-OVERLYING STEEP MIDLEVEL LAPSE RATES (8-9 C/KM)  
ACCOMPANYING AN EML. MODERATE VERTICAL SHEAR WILL BE OVERLYING THIS  
WARM/MOIST SECTOR, AND WILL INCREASE IN MAGNITUDE THROUGH THE  
PERIOD. WHILE THE EXACT CONVECTIVE EVOLUTION IS SOMEWHAT UNCLEAR,  
THE LATEST OBSERVATIONAL DATA AND MODEL GUIDANCE OFFER INCREASING  
CONFIDENCE THAT THREE CONVECTIVE REGIMES (LOCALLY OVERLAPPING) AND  
ACCOMPANYING SEVERE RISK WILL BE FOCUSED WITHIN A CORRIDOR FROM  
NORTH-CENTRAL KS AND ADJACENT FAR SOUTHERN NE SOUTHWARD THROUGH  
WESTERN OK AND THE EASTERN TX PANHANDLE INTO WESTERN NORTH TX, WHERE  
AN ENHANCED AREA HAS BEEN INCLUDED. THESE THREE REGIMES ARE AS  
FOLLOWS:  
  
(1) ASCENT ACCOMPANYING A TROUGH-PRECEDING SPEED MAXIMUM IS EXPECTED  
TO OVERSPREAD THE OPEN WARM SECTOR FROM PARTS OF KS INTO  
SOUTH-CENTRAL NE DURING THE AFTERNOON. DIURNALLY WEAKENING  
CONVECTIVE INHIBITION WILL HAVE THE POTENTIAL TO PERMIT  
UPSCALE-GROWING CONVECTIVE CLUSTERS TO EVOLVE WITHIN THIS REGIME,  
SPREADING NORTHEASTWARD TOWARD THE LOWER/MIDDLE MISSOURI VALLEY INTO  
THE EVENING HOURS. THE AFOREMENTIONED BUOYANCY AND 30-40 KT OF  
EFFECTIVE SHEAR WILL HAVE THE POTENTIAL TO SUPPORT INTENSE  
UPDRAFTS/DOWNDRAFTS CAPABLE OF PRODUCING SEVERE WIND/HAIL. WHILE A  
TORNADO OR TWO CANNOT BE RULED OUT OWING TO MODEST DIRECTIONAL SHEAR  
IN THE LOW LEVELS, THE ANTICIPATED CLUSTER-TYPE CONVECTIVE MODE AND  
LACK OF STRONGER SRH (GENERALLY 175 M2/S2 OR LESS IN THE 0-1-KM  
LAYER) WILL TEND TO TEMPER THE TORNADO RISK. THE EXACT DETAILS OF  
THE SPEED-MAXIMUM-RELATED CONVECTIVE SCENARIO IS SOMEWHAT UNCERTAIN  
OWING TO THE SMALL-SCALE NATURE OF THE TROUGH-PRECEDING  
DISTURBANCES. HOWEVER, THE LATEST MULTI-MODEL CONSENSUS OFFERS  
SUFFICIENT CONFIDENCE IN GREATER SEVERE RISK FOR THE UPGRADE TO  
ENHANCED, AND SIGNIFICANT SEVERE HAIL/WIND WILL BE POSSIBLE.  
  
(2) VERTICAL CIRCULATIONS ACCOMPANYING THE DRYLINE WILL INTENSIFY  
THROUGH THE AFTERNOON FROM PORTIONS OF WESTERN KS INTO WEST TEXAS,  
SOUTH OF OUTFLOW RELATED TO CONVECTIVE CLUSTERS DESCRIBED ABOVE.  
MIDLEVEL HEIGHT FALLS AHEAD OF THE CYCLONE AND SHORTWAVE TROUGH ARE  
FORECAST TO BE OVERSPREADING THE DRYLINE CIRCULATIONS THROUGH THE  
AFTERNOON, ENCOURAGING EROSION OF ANTECEDENT EML-RELATED INHIBITION  
AND SUPPORTING ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT.  
SUBSTANTIVE DRYLINE-ORTHOGONAL MIDLEVEL FLOW ASSOCIATED WITH 40-55  
KT OF EFFECTIVE SHEAR SUGGESTS THAT DISCRETE SUPERCELL STRUCTURES  
WILL LIKELY EVOLVE -- WITH THE GREATEST COVERAGE OF THIS ACTIVITY  
ACROSS THE ENHANCED AREA WHERE DRYLINE CONVERGENCE WILL BE  
STRONGEST. SUPERCELLS THAT DEVELOP ALONG THE DRYLINE WILL SPREAD  
NORTHEASTWARD THROUGH THE EVENING HOURS -- AFFECTING PARTS OF  
WESTERN OK INTO SOUTH-CENTRAL KS AND VICINITY. WHILE SEVERE HAIL  
(POTENTIALLY SIGNIFICANT) AND SEVERE WINDS APPEAR TO BE THE PRIMARY  
HAZARDS, SOME TORNADO POTENTIAL WILL EXIST. NOTABLY CURVED LOW-LEVEL  
HODOGRAPHS ASSOCIATED WITH INCREASING SRH THROUGH THE EVENING HOURS  
WILL SUPPORT SUCH POTENTIAL. HOWEVER, THERE REMAINS A TENDENCY FOR  
FORECAST HODOGRAPHS TO DISPLAY MODEST INFLECTIONS AROUND 3 KM ABOVE  
GROUND, ASSOCIATED WITH THE MASS RESPONSE TO THE TROUGH-PRECEDING  
SPEED MAXIMUM. THIS COULD SUGGEST COMPLEX STORM MODES/INTERACTIONS  
AND UPDRAFT SEEDING THAT COULD TEMPER THE OVERALL TORNADO RISK (IN  
ADDITION TO THE LACK OF A MORE MOIST BOUNDARY LAYER). IF ANTECEDENT  
DIURNAL CONVECTIVE CLUSTERING IN KS WERE TO BE LESS SUBSTANTIAL, THE  
DRYLINE-RELATED SUPERCELL RISK COULD EVENTUALLY EXTEND FARTHER NORTH  
IN KS BY EVENING.  
  
(3) DURING THE LATE EVENING AND INTO THE OVERNIGHT HOURS, STRONG  
DCVA/ASCENT IMMEDIATELY PRECEDING THE MIDLEVEL CYCLONE/SHORTWAVE  
TROUGH IS EXPECTED TO SUPPORT A PROMINENT INCREASE IN CONVECTION  
FROM SOUTHWEST OK INTO SOUTHWEST TX. A SQUALL LINE WILL LIKELY  
EVOLVE FROM THIS ACTIVITY AND SPREAD EASTWARD -- EXTENDING FROM  
PORTIONS OF SOUTH-CENTRAL OK THROUGH SOUTH-CENTRAL TX BY THE END OF  
THE PERIOD. LOCALLY SEVERE WINDS/HAIL WILL LIKELY ACCOMPANY THIS  
ACTIVITY.  
  
...NORTH OF THE ENHANCED AREA FROM PORTIONS OF NE TO THE UPPER  
MISSISSIPPI VALLEY...  
ISOLATED TO WIDELY SCATTERED SEVERE-THUNDERSTORM POTENTIAL WILL  
AFFECT THESE AREAS, NEAR AND SOUTH OF THE AFOREMENTIONED  
NORTH-CENTRAL STATES SLOW-MOVING BOUNDARY. CLUSTERS OF STRONG TO  
SEVERE STORMS WILL LIKELY SPREAD ACROSS THESE AREAS. SEVERE  
HAIL/WIND POTENTIAL WILL BE SUPPORTED BY MODERATELY STEEP MIDLEVEL  
LAPSE RATES OVERLYING A SOMEWHAT MOIST BOUNDARY LAYER (SURFACE  
DEWPOINTS IN THE 60S). HOWEVER, GIVEN THE POTENTIAL FOR CONVECTIVE  
OVERTURNING TO THE SOUTH OF THE AREA TO INHIBIT BUOYANCY ACROSS THIS  
AREA, AND GIVEN THE ANTICIPATED CLUSTER-TYPE CONVECTIVE MODE AMID  
COMPARATIVELY WEAKER LOW-LEVEL AND DEEP SHEAR, CONFIDENCE IN GREATER  
SEVERE POTENTIAL IS LIMITED.  
  
..COHEN.. 05/15/2017  
  

 

[jojo762]

Also, FWIW, despite that I know many of you hate it, Dr. Forbes added a TOR:CON of 5 to Western KS for tomorrow.

[1900hurricane]

Looks like storms are beginning to fire just to my west (near Panhandle).




Sent from my iPhone using Tapatalk

[jojo762]

18Z NAM upped the ante quite a bit across Western OK and the far E TX PH into S KS tomorrow evening... Soundings like this are more common down in OK, as you get into KS you start to see a bit more low-level backing near 700mb so the hodos aren't as good but are still probably sufficient nonetheless. 

Needless to say really, but I have very little doubt that BL moisture will be a legit issue tomorrow...

[okiestormgeek]

11 minutes ago, jojo762 said:

18Z NAM upped the ante quite a bit across Western OK and the far E TX PH into S KS tomorrow evening... Soundings like this are more common down in OK, as you get into KS you start to see a bit more low-level backing near 700mb so the hodos aren't as good but are still probably sufficient nonetheless. 

Needless to say really, but I have very little doubt that BL moisture will be a legit issue tomorrow...

So the tornado threat is increasing for SW and C OK  tomorrow? 

[jojo762]

11 minutes ago, okiestormgeek said:

So the tornado threat is increasing for SW and C OK  tomorrow? 

Possibly for Western/NW/SW OK... Central Oklahoma's tornado threat should be pretty minimal tomorrow. 

Meanwhile 18Z NAM had a dramatic shift toward the global models for Thursday. Actually shows a fairly impressive environment - with some issues/caveats. 

[mob1]

Nice looking supercells in Iowa, this one has some rotation. 

[Jim Martin]

Possible tornado near Calmar, Iowa currently. Storm moving east.

[jojo762]

Well, both the 00Z NAM and the 00z GFS develop a fairly substantial parameter space tomorrow evening across Western OK... Western KS... and perhaps into Northern TX. As it sits now it appears that numerous severe thunderstorms, probably supercells given mid-level flow orthogonal to the DL, will develop across the current ENH risk area by 21-00z. Very large hail and damaging winds would be likely with any discrete convection, with tornadoes also a possibility in the 22-02Z time-frame. Given the progged parameter space, with a 30-50kt LLJ resulting in 200-300m2/s2 0-1KM SRH, MLCAPE of 2000-3000J/KG owing to steep mid-level and low-level lapse rates and sufficient PBL moisture with SFC dewpoints of 64-69F, and substantial deep-layer shear of 45-70kts, would expect several tornadoes with any mature supercell storms. Again, given the discussed parameter space, long-tracking (due to storm motions of ~40kts) strong tornadoes are not out of the question as well.

 

Low LCLs, fairly impressive low-level moisture profiles, and solid low-level CAPE of 50-150J/KG along with substantial low-level directional shear are always a good recipe for tornadoes when you have a strong mid-level jet ejecting at a favorable time in the plains.

[andyhb]

00z DRT sounding had a 70˚F surface Td and deep moist layer to 850 mb. Promising for tomorrow when one also looks at the 00z EPZ sounding with a well-developed, but actually somewhat moderate EML. I have little doubt there will be initiation tomorrow afternoon assuming dewpoints don't underperform severely (and given the source region conditions and strong advection through the day tomorrow, I think they should at least somewhat close to model progs). WV satellite certainly is indicative of a very strong shortwave moving inland southern California right now.

Both the 00z NAM and GFS are indicating some rather prodigious low level shear/moisture tomorrow by 00z thanks to the 40-50 kt LLJ (actually the GFS has a parameter space that would already be conducive to tornadic supercells by 21z). Would probably set up shop near Shamrock or CDS if I were out there tomorrow as it sits currently. Storm motions do look like they will be rather quick given the strong wind fields.

[jojo762]

 Very large ENH risk across the plains... 10% hatched TOR probs in the area you'd expect.
 

DAY 1 CONVECTIVE OUTLOOK    
NWS STORM PREDICTION CENTER NORMAN OK  
0104 AM CDT TUE MAY 16 2017  
  
VALID 161200Z - 171200Z  
  
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST  
NEBRASKA ACROSS KANSAS...WESTERN OKLAHOMA/TEXAS INCLUDING BOTH  
PANHANDLES...  
  
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF THE  
PLAINS EXTENDING FROM THE MIDDLE RIO GRANDE VALLEY INTO WISCONSIN...  
  
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF  
THE PLAINS FROM TEXAS TO UPPER MICHIGAN...  
   
..SUMMARY  
  
SEVERE THUNDERSTORMS ARE EXPECTED TUESDAY INTO TUESDAY NIGHT FROM  
PORTIONS OF THE SOUTHERN GREAT PLAINS TO THE UPPER MISSISSIPPI  
VALLEY, WITH THE GREATEST SEVERE WEATHER RISK FROM SOUTHWEST KANSAS  
INTO WESTERN OKLAHOMA AND THE EASTERN TEXAS PANHANDLE. VERY LARGE  
AND DAMAGING HAIL AND A FEW TORNADOES ARE EXPECTED FROM LATE  
AFTERNOON THROUGH EVENING. A STRONG TORNADO IS POSSIBLE. DAMAGING  
WINDS WILL BE OF PARTICULAR CONCERN FROM NORTHERN KANSAS ACROSS  
EASTERN NEBRASKA AND INTO WESTERN IOWA. HAIL AND WIND ARE ALSO  
EXPECTED OVERNIGHT, ACROSS MUCH OF WESTERN AND CENTRAL TEXAS INTO  
OKLAHOMA.  
   
..SYNOPSIS  
  
A POWERFUL UPPER TROUGH WILL MOVE ACROSS THE FOUR CORNERS REGION  
DURING THE DAY, WITH MID AND UPPER LEVEL JETS NOSING INTO THE  
SOUTHERN PLAINS BY LATE AFTERNOON. TO THE EAST, AN UPPER RIDGE WILL  
REMAIN SITUATED OVER THE SOUTHEASTERN STATES, WITH FAST  
SOUTHWESTERLY FLOW ALOFT ROUNDING THE RIDGE ACROSS THE UPPER  
MISSISSIPPI VALLEY. AT THE SURFACE, A LOW PRESSURE TROUGH WILL  
EXTEND FROM SOUTHERN MN INTO THE CENTRAL HIGH PLAINS BY TUESDAY  
AFTERNOON, WITH PRIMARY SURFACE LOW DEEPENING ACROSS WESTERN KANSAS  
AND INTO NEBRASKA THROUGH THE PERIOD.  
  
SUBSTANTIAL SOUTHERLY LOW-LEVEL FLOW WILL PERSIST ACROSS THE PLAINS  
AROUND THE SOUTHEASTERN HIGH, AIDING IN NORTHWARD MOISTURE RETURN.  
MONDAY EVENING SOUNDINGS INDICATE A MOIST BOUNDARY LAYER ACROSS  
SOUTH TEXAS, AND THIS MOISTURE WILL RAPIDLY SHIFT NORTHWARD DURING  
THE DAY ON TUESDAY. STRONG DESTABILIZATION WILL OCCUR AS A RESULT OF  
INCREASING MOISTURE, SURFACE HEATING, AND COOLING ALOFT, WITH A  
LARGE AREA OF SEVERE THUNDERSTORM POTENTIAL FROM TEXAS INTO THE  
UPPER MISSISSIPPI VALLEY.  
  
...SOUTHWEST KANSAS SOUTHWARD INTO THE EASTERN TEXAS PANHANDLE AND  
WESTERN OKLAHOMA...  
A DEEPENING SURFACE TROUGH ACROSS THE HIGH PLAINS WILL SHARPEN THE  
DRYLINE, WHICH WILL EXTEND ROUGHLY FROM GCK/LBL TOWARD CDS BY 00Z  
WED. MID 60S F DEWPOINTS ARE LIKELY ACROSS THE MOIST SECTOR WHERE  
SOUTHEASTERLY WINDS WILL BE MAINTAINED BENEATH A CAPPING INVERSION.  
FORECAST SOUNDINGS INDICATE POTENTIAL FOR SUBSTANTIAL LOW CLOUDS DUE  
TO THE RAPID MOISTURE ADVECTION. HOWEVER, STRONG HEATING AND MIXING  
ALONG AND WEST OF THE DRYLINE WILL LEAD TO AN UNCAPPED AIR MASS BY  
AROUND 21Z. WIND PROFILES WILL STRONGLY FAVOR SUPERCELLS, ESPECIALLY  
BY OR AFTER 00Z WED WHEN THE LOW LEVEL JET INCREASES TO OVER 50 KT.  
THE COMBINATION OF STRONG INSTABILITY WITH STEEP LAPSE RATES ALOFT  
AND LENGTHENING HODOGRAPHS WILL ALL BUT GUARANTEE SIGNIFICANT HAIL,  
WITH A FEW TORNADOES ALSO EXPECTED. A STRONG TORNADO IS POSSIBLE,  
MAINLY ACROSS THE EASTERN PANHANDLES INTO WESTERN OKLAHOMA, AND INTO  
SOUTHWEST KANSAS.  
  
...WESTERN AND NORTHERN KANSAS INTO SOUTHEAST NEBRASKA AND WESTERN  
IOWA // DAYTIME...  
STRONG HEATING WILL OCCUR OVER WESTERN KANSAS, AS MOISTURE RAPIDLY  
RETURNS NORTH. HERE, THE CAPPING INVERSION WILL BE WEAKEST, AND  
SEVERAL MODELS INDICATE THE LIKELIHOOD OF STORM DEVELOPMENT BY 21Z.  
POTENTIAL EXISTS FOR UPSCALE GROWTH OF A FORWARD-PROPAGATING MCS AS  
THE STORMS DEVELOP ACROSS NORTHERN KANSAS INTO SOUTHERN AND EASTERN  
NEBRASKA BY EVENING. EXTREMELY STEEP LAPSE RATES ALOFT ALONG WITH  
LENGTHENING HODOGRAPHS SUGGEST POTENTIAL FOR SIGNIFICANT WIND  
DAMAGE, AS WELL AS HAIL.  
   
..WEST/NORTHWEST TEXAS INTO CENTRAL OKLAHOMA // TUESDAY NIGHT  
  
AS THE UPPER TROUGH CONTINUES TO NEAR, COOLING ALOFT WILL EVENTUALLY  
RESULT IN A RAPID OVERTURNING OF THE UNSTABLE AIR MASS ACROSS MUCH  
OF WESTERN TEXAS, FROM NEAR THE RIO GRANDE INTO OKLAHOMA. WHILE  
SUPERCELLS ARE POSSIBLE INITIALLY, ALONG WITH LARGE HAIL, VEERING  
WINDS WITH THE COLD FRONT SHOULD RESULT IN A LARGELY LINEAR STORM  
MODE WITH TIME. BOTH DAMAGING WINDS AND HAIL WILL BE POSSIBLE AS  
ACTIVITY MOVES TO NEAR I-35 BY 12Z WED.  
  
..JEWELL.. 05/16/2017  

 

[jojo762]

As convective evolution becomes more certain, would anticipate a MDT risk later on, probably for large hail (possibly for tornadoes as well, depending on how things evolve).

[bjc0303]

Would agree on that, especially for large hail.

[andyhb]

Robust plume of 850 mb moisture setting up from Mexico all the way into W KS already tonight thanks to a 40-50+ kt LLJ.

[Drz1111]

The HRRR shows a wide region of SE winds in SW OK that creates a lot of territory with nice parameters.

http://www.pivotalweather.com/model.php?m=hrrr&p=stp&rh=2017051608&fh=16&r=us_sc&lat=34.5000&lon=-99.7732&metar=

[JasonOH]

HRRR is further south with convection than other CAMs.  It is further south with the dryline bulge, which is what I'm playing.

[1900hurricane]

It's always nice to see the incoming speed max so clearly on WV.

 

[jojo762]

Can already feel the moisture today. With a nice temperature inversion evident a few thousand feet up on the scattered low-level clouds this morning across SC KS and down into OK, also seen on the 12Z area RAOBS. Sufficient moisture is already prevalent across Western OK with widespread 64-65Dt... should only improve per latest guidance to the upper 60s.

[the ghost of leroy]

fixing to head out soon.  not sure where i am headed.

[jojo762]

I'd set up anywhere near Childress to Shamrock, seems to be the area with the best shot at discrete convection in a very favorable parameter space. Of course if you don't want to deal with all the chaser convergence in that area could always try a tad bit further north. 

[1900hurricane]

Shamrock is my target as well, since it seems to be in a good position relative to where the dryline bulge is expected to set up and where the surface winds are most backed. It's easy to slide up and down US 83 if need be too.

[rockchalk83]

Has anyone looked into Thursday any further? NWS Wichita seems skeptical on the degree of rapid moisture return being progged by GFS, NAM. I must admit, it feels like to me the degree of the threat on Thursday hinges on how far northwest the warm front returns. 

[mob1]

We'll see as we get closer if moisture return is an issue, but so far most models have very solid moisture return (relatively early to boot) and being mid to late May lends credence to those solutions. 

[jojo762]

16 minutes ago, rockchalk83 said:

Has anyone looked into Thursday any further? NWS Wichita seems skeptical on the degree of rapid moisture return being progged by GFS, NAM. I must admit, it feels like to me the degree of the threat on Thursday hinges on how far northwest the warm front returns. 

Thursday looks fairly good to me. Uncertainty still exists in the exact location of the WF, but it should still make it well into ICT CWA territory... 12Z NAM verbatim would probably be a tornado outbreak from central KS down into OK basing off of various synoptic scale measures and model parameterizations. 

Unsure about northward and eastward extent of the threat as of now (due to DL/WF location uncertainity) but appears to be a solid day across Oklahoma at the very least with very large hail, damaging winds, and tornadoes all appearing possible ATTM.